Latest from mammals

The idea of recording as many mammals as you can see in 24 hours hasn't caught on the way the birding big day has. But when a team of longtime biologists set out into the field, their efforts netted them some important new information about Northern California's wild mammals -- and a new North American record.

Michael Ellis declares that ringtails register a 9.9 on the cuteness scale, and they were reputed to shack up with miners during the Gold Rush. Yet longtime field biologist Wendy has yet to see one of these small mammals. They are elusive, but not as uncommon as you might think.

Ask most people to name the most important species of our grassland habitats, and they'll probably pick coyotes, golden eagles, or even rattlesnakes. But experts say that the strongest contender of all is the animal eaten by all those other ones: the lowly California ground squirrel, a true keystone of local grasslands. Belowground, the squirrels' lengthy burrows harbor insects, snakes, owls, and even frogs and salamanders that couldn't live in such a dry landscape without the squirrels' help. And above-ground, they've evolved some unusual defenses that allow them to thrive, even as they feed so many others.

A million years ago, in a climate much like ours today, the land around an ancestral bay teemed with large animals: mammoths and saber-tooth cats; bears, horses, and peccaries. By 300 years ago, the mammoths were gone, but grizzlies, elk, condor, and pronghorn were abundant.European settlers wiped out many of those animals, but programs to reintroduce some of them are now under way. Which raises the question: What should a healthy, native megafauna look like now?

The Blackhawk Quarry in Danville points to a time, nine million years ago, when the Bay Area was inhabited by elephant-like browsers, herds of three-toed horses, packs of bone-crunching dogs, and an eight-foot-long-sabertooth salmonid, Where did they all go?